Anvil has enabled me to use a Pi Pico W and create an app to show the water temperature at various levels in a solar hot water cylinder. This lets me know when there is not enough remaining hot water for a shower or bath and prompts me to boost the temperature.
It uses 3 x DS18B20 sensors linked to the Pi Pico W. When the button is clicked the temperatures are updated. These are colour coded either to show whether they are “hot enough” or in the case of the lower sensor whether the temperature is increasing or decreasing which indicates whether hot or cold water is entering the cylinder.
I was using the Anvil Server runtime trial to include a plot of the temperatures during the day but that has now expired so I am using text only.
The benefit of the app is that I can now use gas to heat the hot water only when it is absolutely necessary (rather than by guessing how much hot water is left). This will help save gas/reduce CO2.